1. Field of the Invention
The present invention relates to air assist fuel injection systems and, more particularly, to methods and assemblies for delivering fuel and gas to fuel pressure regulators, fuel injectors, and/or air assist fuel injectors of such air assist fuel injection systems.
2. Description of the Related Art
Conventional fuel injectors are configured to deliver a quantity of fuel to a combustion cylinder of an engine. To increase combustion efficiency and decrease pollutants, it is desirable to atomize the delivered fuel. Generally speaking, atomization of fuel can be achieved by supplying high-pressure fuel to conventional fuel injectors, or atomizing low pressure fuel with pressurized gas, i.e., xe2x80x9cair assist fuel injection.xe2x80x9d
In one conventional configuration of an air assist fuel injection system, an air assist fuel injector is located in the head of an engine, which is adjacent a rail that houses a conventional fuel injector and also defines a mount for the air assist fuel injector. The conventional fuel injector and the rail are configured such that a metered quantity of fuel is delivered from the fuel injector directly to the air assist fuel injector. Additionally, the rail includes a number of passageways that deliver pressurized air to the air assist fuel injector. The air assist fuel injector atomizes the received fuel with the pressurized air and conveys the air and fuel mixture to the combustion chamber of the engine. This conventional air assist fuel injection system typically includes a fuel pressure regulator, such as a diaphragm or differential pressure regulator, which generally maintains the fuel supply pressure at an acceptable level so that proper fuel flow characteristics to and through the injectors are assured. In the conventional configuration, the fuel pressure regulator maintains this fuel pressure at the desired level by maintaining a pressure differential between the fuel supply pressure and a reference pressure, such as the air supply pressure to the air assist fuel injector. The fuel pressure regulator is typically mounted on the rail of the air assist fuel injection system such that an external conduit typically communicates the pressurized gas to the fuel pressure regulator and a conduit in the rail communicates fuel to the fuel pressure regulator. In addition, one or more conduits within the rail deliver pressurized gas to the air assist fuel injector and fuel to the fuel injector. Unfortunately, this conventional configuration is sometimes too large for certain engine applications and is difficult to assemble and incorporate in an engine.
In light of the previously described problems associated with conventional air assist fuel injection systems, embodiments of the present invention strive to provide compact configurations for supplying fuel and gas to fuel pressure regulators, fuel injectors, and/or air assist fuel injectors of air assist fuel injection systems.
In accordance with one aspect of the present invention, an assembly for an air assist fuel injection system includes a fuel injector, an air assist fuel injector, a pressure regulator, a rail, and a cover. The rail has at least one conduit for supplying pressurized gas for a gas reference chamber of the pressure regulator and for the air assist fuel injector. The rail also includes a cavity that receives at least a portion of the pressure regulator, and a passageway that receives at least a portion of the fuel injector and that receives at least a portion of the air assist fuel injector. The cover receives at least a portion of the pressure regulator and the fuel injector, and includes a conduit for fluidly communicating fuel to a fuel chamber of the pressure regulator and to the fuel injector.
In accordance with another aspect of the present invention, an alternative assembly for an air assist fuel injection system includes a rail configured to fluidly communicate pressurized gas to a fuel pressure regulator and to an air assist fuel injector, and a cover configured to fluidly communicate fuel to the fuel pressure regulator and to fluidly communicate fuel to the fuel injector.
Another aspect of the present invention concerns an assembly having an air assist fuel injector, a fuel pressure regulator, a rail having at least one conduit therein configured to fluidly communicate pressurized gas to the fuel pressure regulator and to the air assist fuel injector, a fuel injector, and a cover having at least one conduit therein configured to fluidly communicate fuel to the fuel injector and to the fuel pressure regulator.
In accordance with a further aspect of the present invention, a method includes supplying pressurized gas to a fuel pressure regulator and to an air assist fuel injector via at least one internal conduit of a rail, and supplying fuel to the fuel pressure regulator via at least one internal conduit of a cover that receives the pressure regulator.
In accordance with yet another aspect of the present invention, a method includes supplying pressurized gas to a fuel pressure regulator and to an air assist fuel injector via at least one internal conduit of a rail, and supplying fuel to a fuel injector via at least one internal conduit of a cover that receives the fuel injector.
In accordance with a further aspect of the present invention, a method includes inserting an air assist fuel injector into an engine, attaching an assembly to the engine, the assembly including a fuel injector and a fuel pressure regulator, the rail being configured to communicate pressurized gas to the fuel pressure regulator and the air assist fuel injector, the assembly further including a cover configured to communicate fuel to the fuel injector and to the fuel pressure regulator.
In accordance with another aspect of the present invention an assembly includes a fuel pressure regulator, a rail having internal conduit means for communicating pressurized gas to the fuel pressure regulator and to an air assist fuel injector, and a cover having internal conduit means for communicating fuel to the fuel pressure regulator and to a fuel injector.
In accordance with a further aspect of the present invention a method includes retaining a pressure regulator in a cavity of a rail and a fuel injector in a passageway of the rail by covering the pressure regulator and the fuel injector with a cover configured to communicate fuel to the pressure regulator and the fuel injector, the pressure regulator for maintaining a pressure differential between a fuel supply and a gas supply for an air assist fuel injector.
In accordance with another aspect of the present invention an assembly includes a pressure regulator configured to maintain a pressure differential between a fuel supply and a gas supply, the pressure regulator having a fuel housing defining a fuel chamber and a gas reference chamber housing defining a gas reference chamber, a rail configured to receive at least a portion of the gas reference housing and having an internal conduit configured to supply pressurized gas to the pressure regulator, and a cover attached to the rail and covering the pressure regulator, the cover having a first internal conduit configured to supply fuel to a fuel inlet of the pressure regulator, the cover having a second internal conduit configured to receive fuel from a fuel outlet of the pressure regulator.
In accordance with yet another aspect of the present invention an air assist fuel injection system includes a fuel supply line, a gas supply line, a fuel pressure regulator, a fuel injector, an air assist fuel injector, a rail configured to fluidly communicate gas from the gas supply line to the fuel pressure regulator and to the air assist fuel injector, and a cover configured to fluidly communicate fuel from the fuel supply line to the fuel pressure regulator and to the fuel injector.